The major axis of this huge amphitheatre, from one outside wall to the other, measures 602 feet, the minor 507. The principal outer wall is 157 feet in height, and is divided into four stories.[69] Of these the lowest stands on a substruction of two steps, and originally consisted of a row of eighty arches, between which stood half columns of the Doric order. These outer arches, with the exception of thirty-three archways, have disappeared. Upon these rests a very simple entablature without any of the usual peculiarities of the Doric style, and rather belonging to the Ionic, a mixture of styles not very rare in Rome.[70] The arches are all numbered. These numbers were probably intended to correspond to those upon the entrance tickets and rows of seats, in order that the spectators might find their proper seats with ease. There is a staircase and a vomitorium corresponding to every four arches, and the vomitoria as well as the entrance arches were all numbered to prevent confusion. A ticket for the amphitheatre at Frosinone has been found. It bears an inscription CAN. VI IN. X. VIII., thus giving the position and number of the seat. The arches which stood at the extremities of the minor axis were the approaches to the imperial pavilions. They were ornamented with marble columns and carved work on the exterior, and led in the interior to a large withdrawing-room, from which there was a separate passage to the emperor’s throne (pulvinar) on the podium. On the Esquiline side the imperial entrance may still be recognised by a slight projection in the substructions, and by the pillars of white marble lying near it, which originally stood on each side. The same arrangement was doubtless made on the Cælian side, where the Emperor Commodus made himself an underground approach. The other two principal entrances at the extremities of the major axis lead directly into the arena, and were probably used for the entry of processions or marching bodies of gladiators, or machines of various kinds. The entablature of the first story is surmounted by an attica, with projections corresponding to the columns below. Above these stand the arches of the second story, between which half-columns of the Ionic order are placed. The details of the architecture here are in a very meagre style, for the spiral lines on the volutes are omitted, and also the usual toothed ornaments of the entablature. The same remark applies to the third story, the half-columns of which have Corinthian capitals with the acanthus foliage very roughly worked. The fourth story has no arches, but consists of a wall, pierced with larger and smaller square windows placed alternately, and is decorated with pilasters of the Composite order. Between each pair of pilasters three consoles project from the wall, and above these are corresponding niches in the entablature. The purpose of these was to support the masts upon which the awnings were stretched.